rust: kernel: move `allocator` module under `alloc`

We will add more to the `alloc` module in subsequent patches (e.g.,
allocation flags and extension traits).

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-2-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
new file mode 100644 (file)
index 0000000..9aa5077
--- /dev/null
+++ b/rust/kernel/alloc.rs
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Extensions to the [`alloc`] crate.
+
+#[cfg(not(test))]
+#[cfg(not(testlib))]
+mod allocator;

diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
new file mode 100644 (file)
index 0000000..01ad139
--- /dev/null
+++ b/rust/kernel/alloc/allocator.rs
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Allocator support.
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::ptr;
+
+use crate::bindings;
+
+struct KernelAllocator;
+
+/// Calls `krealloc` with a proper size to alloc a new object aligned to `new_layout`'s alignment.
+///
+/// # Safety
+///
+/// - `ptr` can be either null or a pointer which has been allocated by this allocator.
+/// - `new_layout` must have a non-zero size.
+unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gfp_t) -> *mut u8 {
+    // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first.
+    let layout = new_layout.pad_to_align();
+
+    let mut size = layout.size();
+
+    if layout.align() > bindings::ARCH_SLAB_MINALIGN {
+        // The alignment requirement exceeds the slab guarantee, thus try to enlarge the size
+        // to use the "power-of-two" size/alignment guarantee (see comments in `kmalloc()` for
+        // more information).
+        //
+        // Note that `layout.size()` (after padding) is guaranteed to be a multiple of
+        // `layout.align()`, so `next_power_of_two` gives enough alignment guarantee.
+        size = size.next_power_of_two();
+    }
+
+    // SAFETY:
+    // - `ptr` is either null or a pointer returned from a previous `k{re}alloc()` by the
+    //   function safety requirement.
+    // - `size` is greater than 0 since it's either a `layout.size()` (which cannot be zero
+    //   according to the function safety requirement) or a result from `next_power_of_two()`.
+    unsafe { bindings::krealloc(ptr as *const core::ffi::c_void, size, flags) as *mut u8 }
+}
+
+unsafe impl GlobalAlloc for KernelAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+        // requirement.
+        unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+        unsafe {
+            bindings::kfree(ptr as *const core::ffi::c_void);
+        }
+    }
+
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        // SAFETY:
+        // - `new_size`, when rounded up to the nearest multiple of `layout.align()`, will not
+        //   overflow `isize` by the function safety requirement.
+        // - `layout.align()` is a proper alignment (i.e. not zero and must be a power of two).
+        let layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
+
+        // SAFETY:
+        // - `ptr` is either null or a pointer allocated by this allocator by the function safety
+        //   requirement.
+        // - the size of `layout` is not zero because `new_size` is not zero by the function safety
+        //   requirement.
+        unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
+    }
+
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+        // requirement.
+        unsafe {
+            krealloc_aligned(
+                ptr::null_mut(),
+                layout,
+                bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+            )
+        }
+    }
+}
+
+#[global_allocator]
+static ALLOCATOR: KernelAllocator = KernelAllocator;
+
+// See <https://github.com/rust-lang/rust/pull/86844>.
+#[no_mangle]
+static __rust_no_alloc_shim_is_unstable: u8 = 0;

diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
deleted file mode 100644 (file)
index 01ad139..0000000
--- a/rust/kernel/allocator.rs
+++ /dev/null
@@ -1,88 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! Allocator support.
-
-use core::alloc::{GlobalAlloc, Layout};
-use core::ptr;
-
-use crate::bindings;
-
-struct KernelAllocator;
-
-/// Calls `krealloc` with a proper size to alloc a new object aligned to `new_layout`'s alignment.
-///
-/// # Safety
-///
-/// - `ptr` can be either null or a pointer which has been allocated by this allocator.
-/// - `new_layout` must have a non-zero size.
-unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gfp_t) -> *mut u8 {
-    // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first.
-    let layout = new_layout.pad_to_align();
-
-    let mut size = layout.size();
-
-    if layout.align() > bindings::ARCH_SLAB_MINALIGN {
-        // The alignment requirement exceeds the slab guarantee, thus try to enlarge the size
-        // to use the "power-of-two" size/alignment guarantee (see comments in `kmalloc()` for
-        // more information).
-        //
-        // Note that `layout.size()` (after padding) is guaranteed to be a multiple of
-        // `layout.align()`, so `next_power_of_two` gives enough alignment guarantee.
-        size = size.next_power_of_two();
-    }
-
-    // SAFETY:
-    // - `ptr` is either null or a pointer returned from a previous `k{re}alloc()` by the
-    //   function safety requirement.
-    // - `size` is greater than 0 since it's either a `layout.size()` (which cannot be zero
-    //   according to the function safety requirement) or a result from `next_power_of_two()`.
-    unsafe { bindings::krealloc(ptr as *const core::ffi::c_void, size, flags) as *mut u8 }
-}
-
-unsafe impl GlobalAlloc for KernelAllocator {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
-        // requirement.
-        unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
-    }
-
-    unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
-        unsafe {
-            bindings::kfree(ptr as *const core::ffi::c_void);
-        }
-    }
-
-    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
-        // SAFETY:
-        // - `new_size`, when rounded up to the nearest multiple of `layout.align()`, will not
-        //   overflow `isize` by the function safety requirement.
-        // - `layout.align()` is a proper alignment (i.e. not zero and must be a power of two).
-        let layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
-
-        // SAFETY:
-        // - `ptr` is either null or a pointer allocated by this allocator by the function safety
-        //   requirement.
-        // - the size of `layout` is not zero because `new_size` is not zero by the function safety
-        //   requirement.
-        unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
-    }
-
-    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
-        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
-        // requirement.
-        unsafe {
-            krealloc_aligned(
-                ptr::null_mut(),
-                layout,
-                bindings::GFP_KERNEL | bindings::__GFP_ZERO,
-            )
-        }
-    }
-}
-
-#[global_allocator]
-static ALLOCATOR: KernelAllocator = KernelAllocator;
-
-// See <https://github.com/rust-lang/rust/pull/86844>.
-#[no_mangle]
-static __rust_no_alloc_shim_is_unstable: u8 = 0;

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 08dbc3eebaefcf863f13aa03791f7a4dda22227b..1e910fe7c2c774af96171bf174ffc9ee6f945c52 100644 (file)
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -27,9 +27,7 @@ compile_error!("Missing kernel configuration for conditional compilation");
 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
 extern crate self as kernel;
 
-#[cfg(not(test))]
-#[cfg(not(testlib))]
-mod allocator;
+pub mod alloc;
 mod build_assert;
 pub mod error;
 pub mod init;